Transaction fee
TL;DR
A Bitcoin transaction fee is the voluntary payment to the miner for including your transaction in a block, usually expressed in sats per vbyte.
Bitcoin fees are market-driven: expect competition (full mempool) and you bid more sats per vbyte. Miners pick highest-paying transactions first. After 2140 — when block rewards are zero — fees become the entire miner income. A healthy fee market is a long-term security factor.
Example
A simple P2WPKH transaction is ~141 vbytes. At 5 sat/vB: 705 sats (€0.60). At 100 sat/vB: 14,100 sats (€12). Multisig and batching transactions are bigger and costlier.
Frequently asked questions
What is the optimal fee?
Use mempool.space's fee estimator: it shows rates for next block, 3 blocks, 6 blocks. Non-urgent payments often succeed at minimum fee.
Related terms
Further reading
- → Our service: Bitcoin sector